The track bushings used in the track pins for linking the track links for the endless track of a track type machine, such as an earthmoving machine, for example, are subjected to a very severe operating environment. The ends of the track bushing and the inner surface of the track bushing adjacent its two ends are the main bearing surfaces that respectively slide against the track seal and the track pin. The dirt and debris tend to wear the ends of the track bushings sliding against the sealing surface of a track seal. This happens because the dirt and debris particles get lodged between the seal and the bushing end surface and eventually wear a groove into the end face of the track bushing. Further, the particles of dirt and debris tend to work their way into the clearance between the track pin and the bushing and eventually wear the outer surface of the track pin or the inner surface of the track bushing. This type of a wear results in metal-to-metal transfer between the track pin and the track bushing, a phenomenon called "galling".
It is desirable to provide a track bushing that has a very hard, highly corrosion resistant coating that prevents the corrosion and erosion of the end of the track bushing. It is also very desirable to provide a track bushing having a hard coating on its inner surface so as to prevent galling. It is also desirable to generally improve the surface finish of the aforementioned bearing surfaces of a track bushing so that they are more resistant to friction and wear.
The present invention is directed to overcome one or more problems of heretofore utilized track bushings for track-type machines.